Impact of dissociation on the effectiveness of psychotherapy for post-traumatic stress disorder: meta-analysis

C M Hoeboer; R A De Kleine; M L Molendijk; M Schoorl; D A C Oprel; J Mouthaan; W Van der Does; A Van Minnen

doi:10.1192/bjo.2020.30

Impact of dissociation on the effectiveness of psychotherapy for post-traumatic stress disorder: meta-analysis

BJPsych Open. 2020 May 19;6(3):e53. doi: 10.1192/bjo.2020.30.

Authors

C M Hoeboer¹, R A De Kleine², M L Molendijk², M Schoorl¹, D A C Oprel¹, J Mouthaan², W Van der Does³, A Van Minnen⁴

Affiliations

¹ Leiden University, Institute of Psychology; and Parnassiagroep, PsyQ, The Hague, the Netherlands.
² Leiden University, Institute of Psychology, the Netherlands.
³ Leiden University, Institute of Psychology; Parnassiagroep, PsyQ The Hague, the Netherlands; and Department of Psychiatry, Leiden University Medical Center, the Netherlands.
⁴ PSYTREC, Bilthoven; and Radboud University, Behavioural Science Institute, the Netherlands.

Abstract

Background: Many patients with post-traumatic stress disorder (PTSD) experience dissociative symptoms. The question of whether these dissociative symptoms negatively influence the effectiveness of psychotherapy for PTSD is unresolved.

Aims: To determine the influence of dissociative symptoms on psychotherapy outcome in PTSD.

Method: We conducted a systematic search in Cochrane, Embase, PILOTS, PsycINFO, PubMed and Web of Science for relevant clinical trials. A random-effects meta-analysis examined the impact of dissociation on psychotherapy outcome in PTSD (pre-registered at Prospero CRD42018086575).

Results: Twenty-one trials (of which nine were randomised controlled trials) with 1714 patients were included. Pre-treatment dissociation was not related to treatment effectiveness in patients with PTSD (Pearson's correlation coefficient 0.04, 95% CI -0.04 to 0.13). Between-study heterogeneity was high but was not explained by moderators such as trauma focus of the psychotherapy or risk of bias score. There was no indication for publication bias.

Conclusions: We found no evidence that dissociation moderates the effectiveness of psychotherapy for PTSD. The quality of some of the included studies was relatively low, emphasising the need for high-quality clinical trials in patients with PTSD. The results suggest that pre-treatment dissociation does not determine psychotherapy outcome in PTSD.

Keywords: Dissociative disorders; group psychotherapy; individual psychotherapy; post-traumatic stress disorder.